(a) Field of the Invention
The present invention relates to an improved structure of a loudspeaker, and in particular, an improved structure of a picture-frame loudspeaker of high sensitivity m sound producing.
(b) Description of the Prior Art
As shown in FIG. 1, there is shown a conventional flat-type loudspeaker. A magnetic core-52 is mounted within a housing body 51 (center), and the upper circumferential edge of the magnetic core 52 is mounted with a conduit 53 containing a voice coil 531 (solenoid). The conduit 53, closing to the end portion of the magnetic core 52, is combined with a corrugation portion 533 having an outward wave-like shape, and the other end of the conduit 53 is mounted to a medium 532 which is adhered to the surface of a vibration board 5. The output signal of an amplifier is inputted into the voice coil 531 so that a magnetic field is produced to attract the magnetic core 52, and the conduit 53 and the magnetic core 52 produce a reciprocating movement. The medium 532 pushes the vibration board 5 to vibrate air to produce sound. The drawbacks of this conventional structure are that
a. The vibration board 5 has a large mass inertia, and therefore a low driving current will not sufficient to cause the vibration board 5 to produce vibration. As a result, the sound producing sensitivity of the entire loudspeaker is low.
b. Due to the large mass inertia of the vibration board 5, the energy attenuation rate is relative large, and if the position of the medium 532 on the vibration board 5 is not appropriate, the entire level of vibration is not even, and therefore, the sound quality of sound-producing of the loudspeaker is poor.
c. Due to the large mass inertia of the vibration board 5, the conduit 53 needs an extremely large driving force, and the conduit 53 is only supported by the corrugation portion 533, thus, if a large sound is to be outputted, the conduit 53 will become tilting, and the output may be distorted. If the distortion is too serious, the loudspeaker may be damaged.
In view of the above drawbacks, it is on object of the present invention to provide an improved structure of a picture-frame type loudspeaker, which mitigates the above drawbacks.
Accordingly, it is an object of the present invention to provide an improved structure of a picture-frame type loudspeaker, wherein a magnetic core is mounted on a housing body adhered to the rear side of a picture frame, and the circumferential edge of the magnetic core is mounted with a conduit containing a voice coil, and the end section of the conduit, close to the magnetic core, is connected together with a corrugation portion which is combined with the housing body, the middle section of the conduit is connected to a diaphragm and the other end of the conduit is connected to a vibration board within the picture frame via a medium By means of the reaction to the signal current by the voice coil, a magnetic field is produced and a relative movement is formed with the magnetic core, such that the vibration board vibrates to produce sound from the picture frame.
Yet another object of the present invention to provide an improved structure of a picture-frame type loudspeaker, wherein the circumferential edge of the diaphragm is connected to the housing body via a second corrugation portion extended from the diaphragm, such that a support is formed together with a first corrugation portion and the conduit so as to minimize tilting during the movement of the conduit.
Yet a further object of the present invention to provide an improved structure of a picture-frame type loudspeaker, wherein the sound producing sensitivity of the loudspeaker is greatly improved.
The foregoing object and summary provide only a brief introduction to the present invention. To filly appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.
Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.